The objective of this proposal are to study a new organelle of developing spermatozoa termed a dictysome-like structure (DLS). These organelles have been noted in tests of several mammalian species but not in other cells and tissues. They resemble closely the Golgi apparatus but DLS and conventional Golgi apparatus coexist in the same cell. DLS are composed of stacks of 2-20 saccules. Tubular elements of about 100 A diameter bridge the intersaccular spaces. The presence of these bridging elements makes the DLS different from Golgi apparatus and places them as candidates as new organelles unique to certain stages of spermatogenesis. Because DLS contain the distinctive intersaccular bridging elements and appear to carry out some function restricted to requirements unique to late stages of germ cell development in the testis, these structures emerge as potential targets for development of drugs applicable to fertility control in the male. The objective of this study are to investigate DLS of testicular germ cells to learn: 1) More about their structure, function and distribution among species, and 2) to what extent DLS contain unique macromolecules against which specific blocking drugs could be developed. A correlative approach will be emphasized in which information from electron microscopy and cytochemistry will be combined with cell fractionation and biochemical analyses.